How Sleeve-valve Engines Work

Author's Note: How Sleeve-valve Engines Work

As a big military aircraft geek, I had heard of sleeve-valve engines prior to this assignment. But that was about the extent of it. Given their footnote-in-history status, I had always thought of them merely in the abstract. Unlike a poppet valve engine that you can study in your own driveway, these "sleeve-valve things" were to me just a forgotten, if quaint, technology, like steam locomotives. So when I tapped the power of the Interwebs to see them in action, I was instantly struck with both awe and admiration. How did folks 100 years ago figure out all the necessary angles, tolerances, weight balances and more to bring these incredibly complex machines to life? The fact that entrepreneurs today are looking to breathe new life into the concept speaks volumes about those original pioneers' genius and vision. One could argue that the original, twentieth-century sleeve-valve engines were "over-engineered" -- that is, they were too complicated for their own good. Or it could simply be that, lacking the advances in materials science and the precision of computer-aided design that we enjoy today, they were merely ahead of their time.